• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.95-100
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• 2012

We show that the minimum EOP (eye-opening penalty) obtained by tunable dispersion compensation is a function of a figure of merit for a nonlinear process, $I_0L_{eff}$, where $I_0$ is the optical intensity and $L_{eff}$ is the effective length of the interaction region. Using this rule, we do not need to conduct nonlinear simulations in all the cases of signal power and transmission length to obtain the signal distortion in dispersion-managed optical transmission. Instead, we need to conduct a simulation in only one case of a signal power and find the functional relation, and then we can obtain the values of the signal distortion in other cases using the discovered functional relation. This technique can reduce the number of nonlinear simulations to less than 10%.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.3
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• pp.289-295
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• 2005

Instrumentation and Control (I&C) of the Neutral Beam Test Stand (NB- TS) Facility at the Korea Atomic Energy Research Institute (KAERI) for the Korea Superconducting Tokamak Advanced Research (KSTAR) project has been underway since the start of the project to answer the diverse requests arising from the various facets of the development and construction phases of the project. Optical signal transmission constitutes a significant portion of I&C works and has been performed for the entirety of the project. During the NB- TS construction and related experiments, significant achievements to a more accurate as well as more refined optical signal transmissions have been made. Examples of those I&C works that utilized the optical signal transmission are the Langmuir probe signal transmission, gradient grid current signal transmission, gas flow control and signal transmission, ion source temperature measurement, beam line component temperature monitoring, and coolant flow signal transmission, etc. These optical signal transition provisions are now performing part of the indispensable functions for the proper operation of the NB- TS facility. Attained experience and expertise are expected to be well applied to the upcoming main neutral beam injection (NBI) system construction for the KSTAR project.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.77-80
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• 2001

In this paper, it is analyzed the statistical characteristics on the transmission performance of the optical SCM transmission in the CDMA RF signal relay system. Using Mach-Zehnder modulator, optical signal is regenerated into CDMA RF signal. Transfer function model of mach-Zehnder modulator is approximated to the third power of the input signal using Taylor series. BER results are analyzed under the multiple access interference and multi-path fading environment.

• Journal of the Optical Society of Korea
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• v.2 no.1
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• pp.22-25
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• 1998

We present a spectrum broadening technique to improve the signal-to-noise ratio of spectrum sliced incoherent light sources using the fiber four-wave mixing effect which occurs in a nonlinear loop mirror located at the receiver. The initial transmission channel bandwidth of 0.92 nm was increased to 1.62 nm in the nonlinear loop mirror at the optical receiver, which enhances the signal-to-noise ratio to a desired value. Using this technique, we have demonstrated the transmission of a 2.5 Gb/s NRZ signal with the 0.92 nm bandwidth through a 80 km dispersion-shifted fiber. The measured transmission penalty was less than 0.2 dB at $1{\imes}10^{-10}$ BER.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.567-571
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• 2012

To design the long-haul optical communication system, we need to decide the type of optical fiber and optical amplifier, span length of optical amplifier, dispersion compensation method, optical signal power, etc. Therefore, we need to predict the performance of optical communication system when we change one of the system parameters. In this paper, we investigate the method of predicting the maximum transmission length of the designed optical communication system and finding the optimum optical signal power to obtain the maximum transmission length.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1281-1283
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• 1995

In this paper, we develop a prototype of the Optical SCM transmission module. This module is possible to application to electric facilities for control and measurements. Transmission channel number is two channels, namely, image and digital signal. In the image transmission, modulation method is AM, baseband signal is NTSC video signal and demodulation use PLL. Modulation of digital signal is QPSK, 1.544Mbps and demodulation use PLL. First, we calculate theoretical analysis about RF and Optical link in the transmission. This calculation is well correspond with practical system and transmission experiment is excellent, but this is only two channel model. And now, we plan to multichannel transmission to measure intermodulation, frequency assignments and optimal channel numbers et al.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.224-226
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• 2000

Consumer electronics is rapidly digitalized invoking the necessity of digital signal transmission. Moreover, even in consumer electronics, occasionally signal speed is over 1Gbps and long distance transmission(over 5 meters) is required. For these requirements, even though optical transmission is ideal, cost problem has blocked up its entrance to consumer market. However, inexpensive and high speed optical devices such as VCSEL, PIN or MSN PD with large detecting area and low capacitance and Plastic Optical Fiber have been developed so that optical solution can be compete with electrical one in consumer electronics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4462-4466
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• 2013

In optical system, the signal and additive noise for statistical properties of a variety of ways to evaluate the performance of the system is essential for the optimization. In this paper, performance analysis of spectrum-sliced optical system in the optical pre-amplifier in the receiver the received signal by including the error limits for the bit that is, the bit error rate (BER: Bit Error Rate) required to maintain the average optical power represents the number of photons per bit is included in this paper to digital form, noticeable signal the receiver to calculate the sensitivity of the method for the calculation was performed. The general strength of the transmission of the modulated signal and digital signal transmission was required for the comparison of optical power. As shown in Figure 3, the general strength of the digital signal transmission system for transmitting a modulated signal compared with the case is improved by at least 10dB.

• ETRI Journal
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• v.43 no.1
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• pp.133-140
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• 2021

Herein, we present a compact transversal bandpass filter (BPF) with an extremely wide upper stopband and multiple transmission zeros (TZ). Three signal transmission paths with shorted stubs and open-coupled lines allow signal transmission from input port to output port. Two resonant modes can be excited simultaneously and managed easily for bandpass response. Eleven TZs are achieved via transmission path cancelation; an extremely wide upper stopband with an attenuation level better than -12 dB is achieved up to 11.7 f0, where f0 is the center frequency (CF). In addition, bandwidth and CF can be controlled by adjusting electrical lengths. For proof of concept, a wideband BPF centered at 1.04 GHz with 3 dB fractional bandwidths of 49.2% was designed, fabricated, and evaluated. The overall circuit measures 0.045λg × 0.117λg; good agreement was observed between the measured and simulated results.

• ETRI Journal
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• v.29 no.6
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• pp.808-810
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• 2007

We demonstrate 10 Gbps optical signal transmission via long-range surface plasmon polaritons (LR-SPPs) in a very thin metal strip-guided geometry. The LR-SPP waveguide was fabricated as a 14 nm thick, 2.5 ${\mu}m$ wide, and 4 cm long gold strip embedded in a polymer and pigtailed with single-mode fibers. The total insertion loss of 16 dB was achieved at a wavelength of 1.55 ${\mu}m$ as a carrier wave. In a 10 Gbps optical signal transmission experiment, the LR-SPP waveguide exhibits an excellent eye opening and a 2.2 dB power penalty at $10^{-12}$ bit error rate. We confirm, for the first time, that LR-SPPs can efficiently transfer data signals as well as the carrier light.